CTLA4 and neoplasm: Therefore, immune checkpoint therapy, which targets regulatory pathways in T cells, can restore the function of T cells and cause tumour regression. Inhibitors of immune checkpoints, such as antibodies against cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and programmed death ligand-1/programmed death-1 (PD-L1/PD-1) molecules, can release the inhibited immune function of T cells and make the tumour free from immune tolerance, killing tumour cells [3].